Cross-linked and epoxidized cellulosic products



United States Patent Office 3,326,788 Patented June 20, 1967 3,326,788 CROSS-LINKED AND EPOXIDIZED CELLULOSIC PRODUCTS John W. Lynn, Charleston, and Walter J. Skraba, South Charleston, W. Va., assignors to Union Carbide Corporation, a corporation oi NewYork No Drawing. Filed Jan. 29, 1964, Ser. No. 341,096

20 Claims. (Cl. 204159.12)

This invention relates to treatment of'cellulosic mate rials to improve the physical characteristics thereof. More particularly, this invention relates to a process for the preparation of cellulosic products characterized by a plurality of pendant epoxy-containing groups by graft polymerization of a conjugated dienic hydrocarbon, or a mixture of a conjugated dienic hydrocarbon andan ethylenically unsaturated polymerizable comonomer, to a cellulosic substrate and subsequent epoxidation of the olefinic sites in the graft. The invention also relates to the preparation of cross-linked products by curing of the above-described grafted cellulosic materials.

Cellulosic materials have been treated in the past in many ways to modify their physical characteristicsor impart desired properties thereto. Among the techniques employed has been the grafting of various polymerizable monomers having either ethylenic or dienic unsaturation to the cellulosic material. The grafting process usually involves irradiating the cellulosic substrate to formfree radicals in and on the surface thereof which initiate the polymerization of the monomer to form a polymer chain that is chemically bonded to the substrate. The resultant product possesses properties that difier markedly from those of the cellulosic substrate itself.

The present invention provides a novel combination of steps whereby a cellulosic material can be converted to a cellulosic product characterized by a plurality of pendant epoxy-containing groups that are capable of being cross-linked. The essential steps in the method of this invention are: (1) subjecting the cellulosic substrate to high energy ionizing radiation sufficient to produce sites for free-radical initiated graft polymerization thereon, (2) contacting the cellulosic substrate with a conjugated dienic hydrocarbon of from 4 to about 12 carbon atoms for a period of time suflicient to graft polymerize the dienic hydrocarbon to the cellulosic substrate and thereby form a grafted cellulosic material having olefinic sites in the graft, and (3) epoxidizing the olefinic sites, i.e., the carbon to carbon double bonds, of the graft to produce a cellulosic product consisting of a cellulosic substrate having a polyepoxide graft bonded thereto. The grafted cellulosic substrate can then subsequently be (4) contacted with an epoxide curing agent so as to cure the polyepoxide graft, i.e., the pendant epoxy-containing groups, within the fibers of the substrate. Conventional techniques of irradiating polymeric materials, and methods of epoxidizing polydienes and of cross-linking the resulting polyepoxides by means of expoxide curing agents which are well known and Widelyutilized on a commercial basis, are applicable to the present invention; but the unique combination of steps disclosed herein and the resulting improved cellulosic materials were not heretofore known to the art.

The cellulosic materials to which this invention relates are materials composed of substantially all cellulosic fiber. Thus, for example, the cellulosic substrate can be paper, cotton linters, a-cellulose from Wood pulp,. or a cellulosic textile fabric, i.e., cotton fabrics, linen fabrics and rayon fabrics such as those obtained by the viscose acetate or cuprammonium processes. The cellulosic textile fabric can of course consist of blends of cotton, linen or rayon fibers and can contain minor amounts of other textile fibers as long as it is substantially all cellulosic fiber. The physical characteristics of such cellulosic materials can be modified in a desirable manner by subjecting them to the process disclosed herein. Thus, for example, the present invention provides. an effective method of increasing the breaking strength of paper or of preparing shrink and crease resistant cellulosic textile fabrics.

The conjugated dienic hydrocarbons that are grafted to. cellulosic substrates in accordance with the method of this invention are compounds composed solely of carbon and hydrogen which have two conjugated double bonds in the molecule thereof. The suitable conjugated dienic hydrocarbons are those containing from 4 to about 12 carbon atoms. Illustrative of the conjugated dienic hydrocarbons that can be employed, one can mention butadiene-l,3, isoprene, 2,3-dimethyl-1,3-butadiene, Z-ethyl- 1,3-butadiene, 2,3-dibutyl l,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-pentadiene, and the like.

The graft polymer which is schemically bonded to the cellulosic substrate by the method of this invention can be a polymer of one or more of the above-described conjugated dienic hydrocarbons or a polymer of a conjugated dienic hydrocarbon and an ethylenically unsaturated polymerizable comonomer. Thus, the composition which is grafted to the cellulosic substrate can consist of 50 to mole percent of the conjugated dienic hydrocarbon and 50 to 0 mole percent of an ethylenically unsaturated comonomer. The suitable ethylenically unsaturated monomers for the purposes of this invention are compounds of the general formula:

wherein R is independently selected from the group consisting of a hydrogen atom and a methyl group and R is independently selected from the group consisting of a cyano group, a phenyl group, a carboxyl group, a carbamoyl group, an acetoxy group, and a carbonyloxyalkyl group wherein the alkyl moiety contains from 1 to 4 carbon atoms. Illustrative of the ethylenically unsaturated monomers that can be employed, one can mention acrylonitrile, Z-methacrylonitrile, styrene, Z-methylstyrene, acrylic acid, methacrylic acid, acrylamide, vinyl acetate, methyl acrylate, methyl methacrylate, ethyl acrylate, isopropyl acrylate, n-butyl methacrylate, and the like.

Use of a mixture of a conjugated dienic hydrocarbon with an ethylenically unsaturated polymerizable comonomer to form the graft as described above permits greater diversity in the properties of the finished product than use of the conjugated dienic hydrocarbon alone. Thus, for example, grafting of a mixture of acrylonitrile and a conjugated dienic hydrocarbon to cellulosic textile fabrics permits preparation of a fabric having increased resistance to mildew and fungi growths as well as enhanced crease and shrink resistance. Other useful modifications of the properties of cellulosic materials that can be achieved by the method of this invention, for example, improvement in dye receptivity or modification of static propensity, will be apparent to one skilled in the art.

Radiation induced graft polymerization of the conjugated dienic hydrocarbon, or the mixture of a conjugated dienic hydrocarbon and an ethylenically unsaturated polymerizable comonomer, to the cellulosic substrate can be accomplished by any suitable procedure. The essential requirement is that the cellulosic substrate be exposed to high energy ionizing radiation at a suitable dose rate and to a suitable total dosage. The high energy ionizing radiation results in the formation of active sites or centers of reactivity at which grafting to the cellulosic substrate takes place and growth of the polymer chain is initiated. The number of such active sites formed on the surface and in the interstices of the cellulosic substrate and, in consequence, the extent of the graft is dependent primarily upon the total dosage to which the substrate is exposed.

Any suitable source of high energy ionizing radiation can be used in the method of this invention. As is well known to those skilled in the art, the term high energy ionizing radiation denotes radiation which has sufficient energy to produce ions or break chemical bonds. The ionizing radiation can be particle radiation or electromagnetic radiation; that is, the ionizing radiation can be an emission of electrons or nuclear particles, such as protons, neutrons, deuterons or alpha-particles, accelerated to high speeds by means of a suitable voltage gradient produced by, for example, a resonant cavity accelerator, a Van de Graaff generator, a betatron, a synchrotron, or a cyclotron, or the radiation can be ionizing electromagnetic radiation such as X-rays obtained from suitable X-ray equipment or gamma rays obtained from a nuclear reactor or from natural or artificial radioactive materials. The use of radioactive isotopes such as cobalt-60 as a source of gamma rays is a particularly desirable method of producing the required high energy ionizing radiation. Radiation from waste fission products could also be readily utilized in the method of this invention.

The degree of exposure of the cellulosic substrate to the high energy ionizing radiation must be at least sufficient to produce sites for free-radical initiated graft polymerization thereon. The upper exposure limit is dependent upon the stability of the cellulosic substrate and must, of course, be below that level which will result in significant degradation of the cellulosic substrate. It has been found that the graft polymerization is preferably carried out by subjecting the cellulosic substrate to high energy ionizing radiation at a dose rate of from. about 1x10 to about 1X10 roentgens per hour to a total dosage of from about 0.1 to about 10 megarads. The duration of the period during which the cellulosic substrate is exposed to the high energy ionizing radiation is not critical and can vary from a few seconds to many hours, provided the prescribed total dosage and radiation intensity are maintained.

The irradiation of the cellulosic substrate and the contacting of the cellulosic substrate with the monomeric graft polymerizable material, that is, the conjugated dienic hydrocarbon or mixture of conjugated dienic hydrocarbon and ethylenically unsaturated polymerizable comonomer, can be carried out simultaneously or the cellulosic substrate can be pre-irradiated and subsequently contacted with the monomeric graft polymerizable material, as long as the substrate is still in an activated state. The length of time which can be permitted to elapse between the pre-irradiation and the grafting will depend upon such factors as the degree of radiation exposure and the temperature but should, in general, not be more than several minutes and, preferably, the irradiation should be followed by more or less immediate contact of the activated substrate with the aforesaid monomeric graft polymerizable material. The above-described pre-irradiation of the cellulosic substrate can be carried out in vacuo, in air, or in an inert gas such as, for example, nitrogen or argon.

The monomeric graft polymerizable material, i.e., the conjugated dienic hydrocarbon or mixture of conjugated dienic hydrocarbon and ethylenically unsaturated polymerizable comonomer hereinbefore described, can be either gaseous or liquid when brought into contact with the cellulosic substrate. Alternatively, the monomeric graft polymerizable material can be dissolved in an inert liquid solvent such as methanol, hexane, benzene, toluene, ethylaeetate, ethyl ether, dioxane, and the like, or can be uti lized in the form of an aqueous emulsion. With all of 4 these procedures it is necessary to substantially exclude oxygen from the system during the graft polymerization. Thus, one suitable method of carrying out the graft polymerization is to pre-irradiate the cellulosic substrate in an evacuated vessel to the required total dosage, and then introduce the monomeric graft polymerizable material, in either the liquid or vapor phase, into the evacuated vessel while preventing atmospheric oxygen from entering the system. An alternative procedure is to immerse the cellulosic substrate in the inert solvent in a suitable vessel, purge the vessel with an inert gas such as argon or nitrogen to remove all oxygen from the system, introduce the monomeric graft polymerizable material into the vessel, and then subject the system to high energy ionizing radiation. Still another procedure is to irradiate the cellulosic substrate in air to the required total dosage, place the irradiated substrate in a suitable vessel, purge the vessel with an inert gas such as argon or nitrogen, and then introduce a solution of the monomeric graft polymerizable material in the inert solvent into the vessel. Other variations of the above procedures that can be employed will be obvious to persons skilled in the art.

The graft polymerization step of the method of this invention can be carried out at temperatures from about 0 C. or less to about 150 C. or more, more preferably, at temperatures from about 20 C. to about 100 C. As is well known in the art, the rate of grafting to the cellulosic substrate increases with increasing temperature.

The extent of grafting is dependent upon the total radiation dosage, with high total dosages resulting in more extensive grafts, and upon the duration of contact of the activated cellulosic substrate with the monomeric graft polymerizable material. When an inert organic solvent is utilized the extent of grafting can, of course, be varied by controlling the concentration of the monomeric graft polymerizable material in the inert solvent, with higher concentrations resulting in more extensive grafts. The extent of the graft can be varied over a wide range depending on the intended use of the cellulosic material. Generally, the cellulosic substrate is grafted to the extent of from about 1 percent to about 20 percent, or more; that is, the grafted product can consist of from about 1 to about 20 percent by weight of graft polymer and 99 to percent by Weight cellulosic substrate. After the graft polymerization is completed, the grafted cellulosic substrate can be treated with a suitable solvent, for example hot benzene, to remove minor amounts of polymer that are formed without being chemically bonded to the cellulosic substrate.

Epoxidation of the olefinic sites in the graft polymer in accordance with the method of this invention can be effected by any known method of epoxidation which will not detrimentally affect the cellulosic substrate. For example, the grafted cellulosic substrate can be treated with an organic per-acid to epoxidize the olefinic sites in the graft polymer. Illustrative of suitable organic peracids which can be employed as the epoxidant one can mention performic acid, peracetic acid, perpropionic acid, perbenzoic acid, perphthalic acid, and the like. The organic peracids are preferably employed in the form of a solution in an inert solvent. Typical inert solvents which can be used with the peracid in this invention include acetone, ethyl acetate, butyl acetate, dibutyl ether, chloroform, glacial acetic acid, and dioxane, among others. The epoxidation of the grafted cellulosic substrate is preferably conducted at temperatures of from about 0 C. to about 100 C. for a period of several minutes to several hours.

The above-described epoxidation of the olefinic sites in the graft need not be complete. Generally, only a relatively small percentage of the olefinic sites in the graft will be epoxidized by the method described above; however, this is sufficient to provide substantial improvement in the properties of the cellulosic substrate as hereinbefore disclosed.

Curing of the cellulosic product can be carried out by contacting it with a suitable epoxide curing agent which cures the grafted epoxy-containing groups within the fibers of the cellulosic substrate to form a highly branched, cross-linked product. The epoxide curing agents which can be employed are all well known to the art and include, among others, amino compounds such as triethylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, dimethylaminopropylamine, diethylaminopropylamine, and the like; organic and inorganic acids such as citric acid, acetic acid, butyric acid, caproic acid, phthalic acid, tartaric acid, oxalic acid, succinic acid, lactic acid, maleic acid, trimellitic acid, phosphoric acid, boric acid, perchloric acid, and the like, or the anhydrides thereof; and metal complexes such as zinc fiuoborate or amineboranes such as triethanolamine borate, and the like. The amount of curing agent employed is typically from about 0.1 to about 15 perts per 100 parts by weight, based on the weight of the graft. Curing can be made to take place at room temperature with certain curing agents, but usually heat is applied to accelerate the cure. Typically, the curing is carried out at temperatures of from about 50 C. to about 200 C., more preferably from about 100 C. to about 150 C., for periods of at least about 1 minute, and more preferably at least about 2 minutes.

The following examples are given to further illustrate the invention, it being understood that these examples are not intended to be limiting of the invention but merely illustrative thereof.

Example 1 A sample of cotton fabric weighing 6.61 grams was immersed in 95 grams of methanol in a pressure bottle .and the bottle was then chilled in Dry Ice and urged thoroughly with nitrogen gas. Gaseous .but-adiene-1,3 was then charged to the bottle in an amount equal to approximately 50 percent of the weight of methanol, the bottle was capped and exposed at room. temperature to radiation with gamma rays from a cobalt-60 source at a dose rate of 1.7 10 roentgens per hour to a total dosage of 0.3 megarad. The cotton fabric was removed from the pressure bottle, treated with hot benzene, dried in vacuo, and weighed. A weight of 6.93 grams was obtained, showing that the graft of polybutadiene to the cotton fabric amounted to about 5 percent.

The grafted cotton fabric was then treated with a 22 weight percent solution of peracetic acid in ethyl acetate for 3 hours at 50 C. to epoxid-ize the olefinic double bonds in the graft. Following the epoxidation the fabric was Washed with acetone and then with water and dried. Analysis for the epoxide group was made 011 the basis of its reaction with pyridine hydrochloride to form the chlorohydrin and pyridine. In this test, a portion of the grafted fabric was placed in a flask containing 50 ml.

of 4.0 N pyridine hydrochloride and50 ml. of pyridine and heated in a steam bath at 98i2 C. for 2 hours. At the end of this time the flask and contents were cooled to room temperature, drops of bromocresol purple indicator Were added, and the mixture was titrated to a permanent blue end pointwith 0.241 N .alcoholic potassium hydroxide solution. A blank was run in precisely the same manner except that the fabric was untreated cotton cloth. The results of the test indicated that approximately 20 percent of the olefinic double bonds in the graft had been epoxidized.

The polyepoxide grafted cotton fabric was then soaked in a 1.5 percent by weight solution of zinc fluorborate in water at room temperature, the excess solution was wrung out of the fabric, and the fabric was heated at 75 C. for 3 minutes and then at 150 C. for 3 minutes to cure the polyepoxide.

recovery by ASTM method D1295-53T and for washwear index in accordance with the following scale:

Index: Evaluation 5 As ironed. 4 Wearable. 3 Needs ironing. 2 Not acceptable. 1 Very wrinkled.

Ref.: Textile Research Journal, 26, 974 (1956), American Dycstuff Reporter, 48, 37 (19 59).

The treated cotton fabric exhibited a wet crease recovery of 74 percent and a dry crease recovery of 61 percent with a wash-wear index of 4. By comparison, the original untreated cotton fabric had a wet crease recovery of 54 percent, a dry crease recovery of 50 percent, and a wash-wear index of 1.

Example 2 A sample of cotton fabric weighing 6.55 grams was placed in a glass pressure vessel, the vessel was evacuated and the fabric exposed to gamma rays from a cobalt- 60 source at a dose rate of 2.2 10 roentgens per hour to a total dosage of 0.22 megarad. A 10 weight percent solution of butadiene-1,3 in methanol freed of air was introduced into the vessel and the contents were heated to 80 C. and maintained at this temperature for 3 hours to form a graft of polybutadiene. After treatment of the grafted fabric with hot benzene and vacuum drying, the sample weighed 6.74 grams, indicating a graft of 2.9 percent.

Epoxidation of the olefinic sites in the graft and subsequent curing of the polyepoxide were carried out in a similar manner to that described in Example 1 and the treated fabric exhibited similar crease recovery and washwear rating.

Example 3 A sample of cotton fabric weighing 7.13 grams was irradiated in the presence of air by exposure to gamma rays obtained from a cobalt-60 source at a dose rate of 2.2 10 roentgens per 'hour to a total dosage of 0.33 megarad. The irradiated cotton fabric was then immediately transferred to a pressure vessel, the air was evacuated from the vessel and a 10 weight percent solution of butadiene-1,3 in methanol was introduced into the vessel and the contents kept at 80 C. for 3 hours to form a graft of polybutadiene. After treatment of the grafted fabric with hot benzene and vacuum drying the sample weighed 7.49 grams indicating a graft of 5 percent.

Epoxidation .of the olefinic sites in the graft and subsequent curing of the polyepoxide were carried out in a similar manner to that described in Example 1 and the treated fabric exhibited similar crease recovery and wash- Wear rating.

Example 4 p A sample of viscose rayon fabric weighing 7.71 grams Was placed in a 500 ml. pressure bottle which was chilled in -Dry Ice and purged with nitrogen gas while cooling and then 75 grams of methanol, 19 grams of acrylonitrile and 56 grams of butadiene-1,3 were added. The bottle was capped, placed in an aluminum shield and exposed at room temperature to cobalt-60 gamma rays at a dose rate of 1.7 10 roentgens per hour to a total dosage of 0.5 megarad. The rayon fabric was removed from the pressure bottle, washed with methanol, extracted for about 12 hours with refluxing benzene and then for about 12 hours with N,N-dimethylformamide at 50 C., and dried under reduced pressure at 50 C. A Weight of 9.20 grams was obtained, indicating a graft of 19.3 percent. Based on nitrogen analysis of the grafted rayon, the graft consisted of 40 percent acrylonitrile and 60 percent bu'tadiene-1,3.

Epoxidation of the olefinic sites in the graft was carried out in a similar manner to that described in Example 1.

Analysis of the epoxide content of the product by reaction with pyridine hydrochloride in the manner described in Example 1 showed that the grafted rayon fabric contained 0.9 percent oxirane oxygen.

Curing of the grafted rayon fabric was carried out in a similar manner to that described in Example 1 and the product showed significant improvement in crease recovery and wash-wear rating.

Example To a 500 ml. pressure bottle there were charged 6.33 grams of finely divided OL-CEHU1OS6 that had been washed in water and dried under reduced pressure at 50 C. After purging with nitrogen gas, the bottle was capped and the a-cellulose irradiated at room temperature with cobalt-60 gamma rays at a dose rate of 1.7 roentgens per hour to a total dosage of 2.6 megarads. Then 30 grams of isoprene and 120 grams of methanol containing 4 weight percent water were added and the bottle was purged with nitrogen gas, capped, placed in an aluminum shield and heated at 90100 C. for 18 hours. After cooling, the solid reaction product was separated by filtration, washed with methanol, and then washed with benzene in a Soxhlet extractor for a period of 36 hours. The benzene was removed under reduced pressure and the isoprene grafted a-cellulose was dried. A weight of 6.93 grams was obtained, indicating a graft of 9.5 percent. Epoxidation of the olefinic sites in the graft was carried out in a similar manner to that described in Example 1.

Various changes and modifications can be made in practicing the present invention without departing from the spirit and scope thereof, and therefore it is intended to include within the scope of the appended claims all such modifications and variations as may be apparent to those skilled in the art from the description and illustrative examples given herein.

What is claimed is:

1. A process for the preparation of a cellulosic product characterized by a plurality of pendant epoxy-containing groups which comprises the steps of (l) subjecting a cellulosic substrate to high energy ionizing radiation sufficient to produce sites for free-radical initiated graft polymerization thereon, (2) contacting said cellulosic substrate with a conjugated dienic hydrocarbon of from 4 to about 12 carbon atoms for a period of time sufficient to graft polymerize said conjugated dienic hydrocarbon to said cellulosic substrate and thereby form a grafted cellulosic material having olefinic sites in the graft, and (3) epoxidizing said olefinic sites to produce a cellulosic product consisting of a cellulosic substrate having a polyepoxide graft bonded thereto.

2. The process of claim 1 wherein the cellulosic substrate is simultaneously subjected to the high energy ionizing radiation and contacted with the conjugated dienic hydrocarbon.

3. The process of claim 1 wherein the cellulosic substrate is first subjected to the high energy ionizing radiation and then contacted with the conjugated dienic hydrocarbon.

4. The process of claim 1 wherein the cellulosic substrate is cotton.

5. The process of claim 1 wherein the cellulosic substrate is rayon.

6. The process of claim 1 wherein the conjugated dienic hydrocarbon is butadiene-1,3.

7. The process of claim 1 wherein the conjugated dienic hydrocarbon is dissolved in an inert liquid solvent.

8. The process of claim 7 wherein the inert liquid solvent is methanol.

9. A process for the preparation of a cross-linked cellulosic product which comprises the steps of (1) subjecting a cellulosic substrate to high energy ionizing radiation sufficient to produce sites for free-radical initiated graft polymerization thereon, (2) contacting said cellulosic substrate with a conjugated dienic hydrocarbon of from 4 to about 12 carbon atoms for a period of time sufficient to graft polymerize said conjugated dienic hydrocarbon to said cellulosic substrate and thereby form a grafted cellulosic material having olefinic sites in the graft, (3) epoxidizing said olefinic sites to produce a cellulosic product consisting of a cellulosic substrate having a polyepoxide graft bonded thereto, and (4) contacting said cellulosic product with an epoxide curing agent so as to cure said polyepoxide grade within the fibers of said cellulosic substrate.

10. A process for the preparation of a cross-linked cellulosic product which comprises the steps of (1) subjecting a cellulosic substrate to high energy ionizing radiation sufficient to produce sites for free-radical initiated graft polymerization thereon, (2) contacting said cellulosic substrate with a monomeric graft polymerizable material consisting of 50 to mole percent of a conjugated dienic hydrocarbon of from 4 to about 12 car-bon atoms and 50 to 0 mole percent of an ethylenically unsaturated polymerizable comonomer having the general formula:

wherein R is independently selected from the group consisting of a hydrogen atom and a methyl group and R is independently selected from the group consisting of a cyano group, a phenyl group, a carboxyl group, a carbamoyl group, an acetoxy group, and a carbonyloxyalkyl group, wherein the alkyl moiety contains from 1 to 4 carbon atoms, for a period of time sufficient to graft polymerize said monomeric graft polymerizable material to said cellulosic substrate and thereby form a grafted cellulosic material having olefinic sites in the graft, (3) epoxidizing said olefinic sites to produce a cellulosic product consisting of a cellulosic substrate having a polyepoxide graft bonded thereto, and (4) contacting said cellulosic prodnot with an epoxide curing agent so as to cure said polyepoxide graft within the fibers of said cellulosic substrate.

11. A process for the preparation of a cross-linked cellulosic product which comprises the steps of (1) subjecting a cellulosic substrate to high energy ionizing radiation at a dose rate of from about 1x10 to about 1 10 roent-gens per hour to a total dosage of from about 0.1 to about 10 megarads, (2) contacting said cellulosic substrate with a monomeric graft polymerizable material consisting of 50 to 100 mole percent of a conjugated dienic hydrocanbon of from 4 to about 12 carbon atoms and 50 to 0 mole percent of an ethylenically unsaturated polymerizable comonomer having the general formula:

wherein R is independently selected from the group consisting of a hydrogen atom and a methyl group and R is independently selected from the group consisting of a cyano group, a phenyl group, a carboxyl group, a carbamoyl group, an acetoxy group, and a carbonyloxyalkyl group wherein the alkyl moiety contains from 1 to 4 carbon atoms, for a period of time sufficient to graft polymerize said monomeric graft polymerizable material to said cellulosic substrate and thereby form a grafted cellulosic material having olefinic sites in the graft, (3) epoxidizing said olefinic sites to produce a cellulosic product consisting of a cellulosic substrate having a polyepoxide graft bonded thereto, and (4) contacting said cellulosic product at a temperature of from about 100 C. to about C. for a period of at least about 2 minutes with an epoxide curing agent so as to cure said polyepoxide graft within the fibers of said cellulosic substrate.

12. The process of claim 11 wherein the cellulosic substrate is cotton.

13. The process of claim 11 wherein the cellulosic substrate is rayon.

14. The process of claim 11 wherein the conjugated dienic hydrocarbon is butadiene-1,3.

15. The process of claim 11 wherein the ethylenically unsaturated polymerizable comonomer is acrylonitrile.

16. The process of claim 11 wherein the epoxidation of the olefinic sites in the graft is carried out by contacting the grafted cellulosic material with a solution of peracetic acid in an inert solvent.

17. The process of claim 11 wherein the epoxide curing agent is an aqueous solution of zinc fiuoborate.

18. A process for imparting wash and wear properties to cotton which comprises immersing cotton fabric in a solution consisting of about 50 percent by weight butadiene-l,3 and the remainder methanol, subjecting the immersed fabric to cobalt-60 gamma rays at a dose rate of about 1x10 roentgens per hour to a total dosage of about 0.2 megarad to form a grafted cotton fabric, contacting the said grafted cotton fabric for about 3 hours at about 50 C. with a solution of about 20 weight percent peracetic acid in ethyl acetate to epoxidize the olefinic sites in the graft and form a polyepoxide-grafted cotton fabric, contacting said polyepoXide-grafted cotton fabric with a solution of 1.5 weight percent zinc fluoborate in water, heating said polyepoxide-grafted cotton fa i t a t 5 C- f r a t 3 m te and t e at product produced by References Cited UNITED STATES PATENTS 2,789,030 4/1957 Fetscher 26017 2,907,675 10/1959 Gaylord 204-159.15 2,998,329 8/1961 'Sovish et a1 204159.12 3,121,698 2/1964 Orsino et al. 26017 3,206,273 9/1965 Munzel et al. 204l59.12

OTHER REFERENCES Fibers and Plastics, July 1961, p. 190.

SAMUEL H. BDECH, Primary Examiner. MURRAY TILLMAN, Examiner. R. B. TURER, N. F. OBLON, Assistant Examiners. 

1. A PROCESS FOR THE PREPARATION OF A CELLULOSIC PRODUCT CHARACTERIZED BY A PLURALITY OF PENDANT EPOXY-CONTAINING GROUPS WHICH COMPRISE THE STEPS (1) SUBJECTING A CELLULOSIC SUBSTRATE TO HIGH ENERGY IONIZING RADIATION SUFFICIENT TO PRODUCE SITES FOR FREE-RADICAL INITIATED GRAFT POLYMERIZATION THEREON, (2) CONTACTING SAID CELLULOSIC SUBSTRATE WITH A CONJUGATED DIENIC HYDROCARBON OF FROM 4 TO ABOUT 12 CARBON ATOMS FOR A PERIOD OF TIME SUFFICIENT TO GRAFT POLYMERIZE SAID CONJUGATED DIENIC HYDROCARBON TO SAID CELLULOSIC SUBSTRATE AND THEREBY FORM A GRAFTED CELLULOSIC MATERIAL HAVING OLEFINIC SITES IN THE GRAFT, AND (3) EPOXIDIZING SAID OLEFINIC SITES TO PRODUCE A CELLULOSIC PRODUCT CONSISTIING OF A CELLULOSIC SUBSTRATE HAVING A POLYEPOXIDE GRAFT BONDED THERETO. 